Over the years, various combinations of chain and rubber or plastic pads or belts have been devised and used in the conveyor field. These have included devices in which the pad or high friction member is a continuous band, similar to a belt, which is mounted on the chain. Other devices include individual pads, one of which is mounted on each link of the chain, or pads of greater length designed to overlay a number of adjacent links of the chain. Examples of these types of construction are found in patents such as U.S. Pat. No. 2,792,928 entitled "Attachment Clip For Lumber Conveyor Chains" issued May 21, 1957 to W. G. Holz; U.S. Pat. No. 3,189,161 entitled "Powered Roller Curve" issued June 15, 1965 to D. A. Schneider et al; U.S. Pat. No. 3,306,430 entitled "Belt-Chain Combination Drive" issued Feb. 28, 1967; and U.S. Pat. No. 4,074,805 entitled "Installation Equipment With A Driving Mechanism" issued Feb. 21, 1978 to Bodewes.
While each of the constructions disclosed by the preceding patents has various merits, these pad and chain combinations have not been entirely satisfactory. While they have provided the advantage of the strength of a chain and the high frictional characteristics of the rubber or plastic pad, they have failed to solve the problem of excessive noise. They have also failed to solve the problem of quick and inexpensive replacement when sections of the pad are damaged, lost, or excessively worn. Despite these shortcomings, the advantage of this type of a combination has been recognized and as a result has been extensively used because the combination provides a propelling member or drive which has wear characteristics much improved over belts, and eliminates the dual problems of tracking and stretch, which are experienced with even the best belt-driven conveyor system.